Wheel units are electronic devices, which are used to monitor wheel properties or parameters. For example, monitoring a tire pressure has become part of governmental regulations in many countries, such that tires or wheels of vehicles are equipped with tire pressure measurement devices, which communicate signals indicative of a tire pressure to a control unit or controller of the vehicle. For example, tire pressure values can be determine and displayed to a user of the vehicle, warning indications can be generated if the tire pressure decreases below a critical threshold.
During manufacturing, production and service of the vehicles, wheels or tires, there may be a desire to communicate with wheel units, for example, for programming, configuration, set up, or security purposes. For example, a wheel unit of a Tire Pressure Monitoring System (TPMS) may have a need of a possibility to receive data during production or service. Today, a means to transfer data is electromagnetic radiation at 125 kHz, which is also referred to as Low Frequency (LF) communication. For example, production lines and service facilities are equipped with 125 kHz electromagnetic data transmitters. The wheel units are equipped with corresponding LF-receive antennas or coils, LF-receivers, respectively. In general the wheel units may transmit and receive data.
For example, data transmission, from the perspective of the wheel unit, may be done via a Radio Frequency (RF) transmitter in an Industrial, Scientific, and Medical (ISM)-band like 315 MHz or 434 MHz. Moreover, an active circuitry of the RF transmitter may be integrated on chip and an external RF antenna circuitry may comprise antenna matching, usually made of capacitors and inductors, and an RF antenna, which can be printed on a Printed Circuit Board (PCB) or be implemented using thick wires or even a metal bar. E.g. data reception, from the perspective of the wheel unit, may be done via an LF-receiver at 125 kHz.